Lubricating oil detergent



Patented July 25; 1950 James '0. Clay'tomflierkeley, "andllorr'jfl Efller,

.-,Albany,Gali.,-assignors to California Research -1Qorporation, ;-San,-. Francisco,ciflalit,,-za;zcorpozation of -Delaware ,;No:.llrawing. uApplicationillecember' fillglllfl, "Serial No. 17.945810 "fThisinvention --relatesto':reliucing the forma- -#tiorro'i gum 'depositsresulting"fromithe iieteriora- "tion ".of lubricating Loil *byincorporatingtherein v icertain saltsf'iselenium containing acids.

Ordinarily,flubricatingh oilsfieteriorate *arr'd,i-in

.:general, *form :gums "when they are "exposed to oxygen 'at elevated temperatures. lf or "example,

crankcase oils, transmission oils, and the like have n "a tendency to" break down "during the operation of e-eng'ines, mesrilting in the formation of sums. The gums Which:are formed collect in the oil rings and the oil lines to cause the sticking of .the piston; rings-and to inhibit the "free fellow :o'ffthe lubricating oil. Thus, the parts'of thvmotors and "gears requiring lubrication -sufier from the slack of proper".lubrication. in order torreduoe the formation of gum depo'sits, it is essential to sincorporate, certain .agentsto. serve as detergents.

.The presenceotdetergentsmeduce the-(formation :of gn-m deposits and permits-the gparts ofsaneenagine tor: example, ttolreceiue ethegt'properlubrica- I ution, -eliminating unnecessary wear of parts. 541116 ;:.to1impropenlubrication.

- .:Many of the internal reombustion engines xof etodayeoperate-eat,higher temperatures andhigher compressions than heretofore with-lakresulting greater stress upon the lubricatin voils and the more :rapid deterioration of these oils. Thus, modern internalmombustion engines, especially -thoseofthe Diesel type, become fouled "andde- 3 velop pistonrring sticking morequickly.than-=-did rstandpoint, the hard alloys eare' motezreadilyrcomroded by eer-tam :mineral (OHS, Flay -used mills in which acidicmmductsrofroxidation havecaccumulate'd and by gtheraction i (believed be 159711 "sindirect;noatalytimention ratlrerrthans srlirect-rnoruzcium .-stearate and :oalcium vnaphthenazte which are-somei:innes-:atidetiL-to: oiisrttoiairihibitwiston ring iflft" isxa Iurtherfibjet. of thi .invention .togproslide -useflil compounds of selenium acapable sof improving hydrocarbon oils.

.These and, other vobjects .will .be apparent 'from thetollowingdescriptionand:olaims.

.Inraccordance .withetheinvention, vthere is incorporated in-a lubricating oil a smallamount of a polyvalent metal-salt of seleninic -aciti dfxithe followingformul'a:

tai s-011 wherein R mayvbe an aliphatic radical ganalkaryl ,r-raclicalror anearal'kyhradical. -;The R vtraldicalimay .;;contai-n, :asssubstituents, epola'r {groups :such as -zchlor-ine,'. bromine,'rhydroxylgethenaketoymercapstoretc.

The .base ssubstance in which the --tpoiyvalent metal salt of the seleni-nic -uacidisiincorporated will normally be petroleumplubricating oilsaand synthetic 'o'ilsoflubi'icati lgsviscosity. These oils may range in viscosityTrom'spindle oils to cylin- --den -stocks.

Uhegpcrlyualent rnetal cations of'theesa'ltspf this .ainventionzaretthefm'etals-of Groups II, I1I, 'IVran"d WI mi 113113 .zpeniodie table sspecifically, calcium, :strontium, ii'harium, 'cadmium, zinc, aluminum, cchremiummlead:rzandi'tin. It is-preferre'd'to use rcalcium, :bar'ium andczinc @metal salts,= sincethese arefamoresefiective detergents 1 than the salt or Z-the other:metalsrlisted hereinabove.

In the aabovef formul-afl-theiR may be an alkyl radical, zansaralky1 radicalor an: alkaryl -'radical. These radicals may be straight-chained,"branchchained, saturated or unsaturated, containing from lfl-wto-Aflacanbon atoms. It is preferred to use straightchained, saturated aliphatic radicals '-'having"from"l2"to':24 carbon atoms. The R group may be exemplified-by-the following "radicals: -decyl,-dodecyl, 'tetradecyl, "cetyl, o'cta'ciecyl, "tetra- -contyl, kdotriacontyl, isoamyl "phenyl, "tributyl phenyl, cetyl phenylp-amyl-naphthyl, etc.

frOrdinarily to-teifect .detergency inaa lubricatpin oilsithesamountr of-assalt .rof za seleninic acid whichris.includedhinsthe oil-1compositiontwill de- "ros'ive act-ion) ofwcertain additives;su'chias celpends oncthetoxidationdead-of -.-the composition. That is, an oil composition which is-used--under con'ditions: resulting'inilarge"amounts of oxidation sprodu'ctstbeingfformed inrtheaoil composition will reguireLlarger-: amounts of' salts of .seleninicracids less or as high as 2% or more. Preferably, 0.2% to 1% of a salt of a seleninlc acid will be used in the practice of this invention. All percentages are by weight based on finished composition.

Concentratespr stock solutions containing 2% to 50% orjniore-of a metal salt are seleninicsacid dispersed in an organic liquid ((2. g., mineral lubricating oil) may be prepared for later blendin 7 H with the substance to be stabilized to produce a finished product.

The following examples will illustrate the practics and the advantages of jthis inventioni Example I .-Preparation ofidodecane-I-selenifiic acid 64 milliliters of concentrated nitrlc-acid (d:

ninate. An excess of a 20% calcium chloride solution was added to the solution of potassium hexadecane-l-seleninate to precipitate the calcium hexadecane-l-seleninate. The analysis of the, ..oalc iurg r hexade cane l seleninate was as 1.4) was slowly added with stirring to 24.8 grams of pure didodecyl clisenlenide. The temperature: l

was maintained at approximately 50 C. for 10 minutes. Water was then added to the mixture to precipitate out the n-dodecyl selenini c acid. The product which was obtained had the following analysis:

Theoretical for Dodecane-I-Seleninic Acid Found Percent Se, 28.3..;... 281 Equivalent Weight, 2 p 281 Melting Point 80. 5-81 Example [Ir-Preparation of calcium dodecemel-selenlnate A solution of grams of dodecane-l-seleninic acid in 95% alcohol was neutralized with 51% aqueous potassium hydroxide at room temperature to form the potassium salt. The calcium salt was precipitated by adding an excess of a 20% calcium chloride solution to the solution of potassium dodecane-l-seleninate.

Example III.-Pr' eparation of hexadecane-1 v selem'm'c acid. r I Twenty grams of crude n-hexadecyl selenocya- .nate was stirred with excess concentrated nitric acid '(d=1.4) for two hours at-room temperature.

This mixture was then kept standing at room temperature for 15 hours, then heated to=65 C. for threehours. When this mix was cooled to 'room'temperature, the reaction product solidified and was separated from the aqueous layer by filtration. The crude hexadecane-l-seleninic acid was purified by crystallization from ethyl ether.

The analysis of the resulting hexadecane-l-seleninic acid was as follows:

Calculatedio r omuaseozu Fmmd Equiv alent Weight 337. 5 338 Example IV.--Prepara-tion of calcium hexadecane-I-selem'nate- I A solution of 44 grams of hexadecane -l-seleninic acid in 95% alcohol was neutralized with 51% aqueous potassium hydroxide at room temperature to form potassiumjhexadecane-leseld mixing the two solutions, a clear solution resulted which, however. began to deposit a solid in about 10 seconds and the solution then set to a solid. An additional cc. of alcohol were stirred in and the mixture was allowed to stand at 40 4. for 2 hours. It was then poured into water and theoil that separated was extracted with ethyl ether.

The ethyl ether extract was washed with water and dried over sodium sulfate and the ether removed by evaporation. The residue was .crystallized'i'rom-a-'mlxture of ether and alcohol. The resulting p c w e? fies-eels 1 91??? P a e l t mta #9992 13, 9-

Example V.'Preparation of octadecane-I-selenz'm'c acid.

jSixty-five'milliliters Of concentrated nitric acid (d=" 1.4) was slowly added with stirring to 34 grams of pure dioctadecyl diselenide at 50 C. The dioctadecyl diselenide was prepared accordingto the method in above Examplelior didodecyl diselenide. The resulting mix was a paste, which was stirred for several hours at 50 C., 'then diluted with 300milliliter's of water to precipitate crude octadecane l-seleninic. acid, which was purifiedby crystallization from hot ethyl alcohol. The analysis of the .octadecane- -l-seleninic acid as follows:

Calculated for CISHUSBOH Fmlnd Pircentsenh... 21.6 21.7 Equivalent Weight 1 365. 5 365 .Melting Point .'....C 5 -94 Example VI .-Preparation of zinc octadccane-I- seleninate A solution of 25.4 gramsof zinc acetate in 300 milliliters of 50% ethyl alcohol was added slowly with'stirringto 96 grams of octadecane-l-seleninic acid in 300 milliliters of hot ethyl alcohol. Zinc octadecane-l-selen'inate' precipitated as a white finely divided substaiice which was washed in-water and dried in'vacuo over calcium chloride.

'The analysis of thezin c octadecane-l-seleninate was as follows:

Theoretical for (OmHsr-SOahZn Percent Se.."..... 19.8 18.5 Porcent'Zn 8.2 7.7

The salts of this invention were compounded in a refined Western SAE 30 oil and testedina Lauson. gasoline engine. The test wascarried out as follows: A single cylinder Lauson gasoline .spark ignition engine, 2%, inch bore and 2 inch stroke, loaded with a three-phase induction generator, was operated under extremely severe conditions designed to develop fully the tendency'of the crankcase lubricant to deteriorate with gum formation and piston ring sticking. The engine was operated at 1200 revolutions per minute, the engine jacket temperature was imaintained at 375 F., the crankcase oil was maintained at 300 F. and the engine-was inspected aftera 30 ,hour .period of .operationand after a fiohour' period of operation. I

.It appears that-the. polyva-lentvmetal salts of seleninic acids (e..g., the zincsalts and the'calcium-salts): have greater detergent action:than other detergent compounds (e. I g-., sulfonates) when ,used in lubricating oils. v '1 :Table: 1: presents the. test results obtained. inza Lauson engine test. The P. D. No. :LPiston :Dis-

coloration Number) as used in the Table I involves a careful inspection of the piston skirt to determine the degree of discoloration of the piston skirt. A completely black piston was assigned a P. D. No. of 800, and a completely clean piston was assigned a P. D. No. of 0. Piston discoloration numbers between 0 and 800 were given to pistons which ranged from totally clean to totally black.

The polyvalent metal salt of seleninic acid compounding of the invention may be used as the only compounding, or it may be used in conjunction with other compounding agents, such as organic sulfides (e. g., dicetyl sulfide); sulfonates, such as calcium alkylbenzene sulfonate; phosphates (e. g., zinc cetylphenyl thiophosphate); phenates (e. g., calcium cetylphenate) etc.

In addition to the polyvalent metal salt of a seleninic acid, the finished oils of the invention may contain other agents, such as extreme pressure agents, blooming agents, pour point inhibitors, etc.

We claim:

1. A composition of matter consisting essentially of a major proportion of a mineral lubricating oil which is susceptible to deterioration when exposed to oxygen and, in an amount sufficient to improve the detergency of said lubricating oil a polyvalent metal salt of a seleninic acid.

2. The composition of claim 1, wherein said lubricating oil is a petroleum lubricating oil.

3. The composition of claim 1, wherein said polyvalent metal salt is a salt of a metal of the second group of the Periodic Table.

4. A composition of matter consisting essentially of a major proportion of a hydrocarbon oil which is susceptible to deterioration when exposed to oxygen and a, small amount, sufficient to improve the detergency of said lubricating oil, of a polyvalent metal salt of a seleninic acid having a direct carbon to selenium linkage, said seleninic acid containin at least carbon atoms.

5. The composition of claim 4, wherein said lubricating oil is a petroleum lubricating oil.

6. The composition of claim 4, wherein said polyvalent metal is zinc.

'7. The composition of claim 4, wherein said polyvalent metal is calcium.

8. The composition of claim 4, wherein said polyvalent metal is barium.

9. The composition of claim 4, wherein said seleninic acid is hexadecane-l-seleninic acid.

10. The composition of claim 4, wherein said seleninic acid is octadecane-l-seleninic acid.

11. The composition of claim 4, wherein said seleninic acid is dodecane-l-seleninic acid.

12. A lubricant comprising a major portion of a mineral oil of lubricating viscosity and about 0.1% to 2% by weight based on the finished lubricant of a polyvalent metal salt of a seleninic acid of the formula wherein the R. is an alkyl radical containing from 10 to 40 carbon atoms.

13. A lubricant of claim 12, wherein said polyvalent metal salt of a seleninic acid is calcium hexadecane-l-seleninate.

14. A lubricant of claim 12, wherein said polyvalent metal salt of a seleninic acid is zinc octadecane-l-seleninate.

15. A lubricant comprising a major portion of a mineral oil of lubricating viscosity and about 0.1% to 2% by weight based on the finished lubricant of a polyvalent metal salt of a seleninic acid of the formula wherein the R is an organic radical selected from the group consisting of alkyl and alkaryl radicals, said organic radical containing from 10 to 40 carbon atoms.

JAIWES O. CLAYTON. DORR H. ETZLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,350,783 Lincoln June 6, 1944 FOREIGN PATENTS Number Country Date 1278'? Great Britain of 1914 OTHER REFERENCES Text Book of Inorganic Chemistry, vol. 2G, part IV by Goddard; Chas. Griflin & Co., 1937, pp. 15 and 16 pertinent. 

1. A COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL WHICH IS SUSCEPTIBLE TO DETERIORATION WHEN EXPOSED TO OXYGEN AND, IN AN AMOUNT SUFFICIENT TO IMPROVE THE DETERGENCY OF SAID LUBRICATING OIL A POLYVALENT METAL SALT OF A SELENINIC ACID. 